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IBM i Navigator CVE-2026-93744

| EUVDEUVD-2026-106858 MEDIUM
Improper Authentication (CWE-287)
2026-10-20 psirt@us.ibm.com GHSA-74rc-m28c-966r
6.5
CVSS 3.1 · Vendor: us
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach exposed Navigator HTTP endpoint
  2. Delivery
    Send crafted pre-auth request to any URL
  3. Exploit
    Bypass improper access control
  4. Execution
    Alter server-side session security state
  5. Impact
    Weaken authentication restrictions

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication mechanism validation
MITRE ATT&CK

2 techniques across 2 tactics: Defense Evasion, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires network reachability to the IBM i Navigator (Navigator for i) web application HTTP service; the attacker sends a crafted request to any Navigator URL before authenticating, exploiting improper access control to modify server-side session security state. No authentication is required (PR:N), no user interaction is needed (UI:N), and attack complexity is low (AC:L), so default-exposed Navigator interfaces are at risk. The principal limiting factor is exposure: the Navigator management interface must be network-accessible to the attacker (e.g., not firewalled to administrative networks), and impact is confined to session security-state alteration (C:L/I:L) rather than full account takeover or code execution.

Impact

This is a genuine but moderate-priority issue. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N) confirms a network-reachable, low-complexity, unauthenticated attack requiring no user interaction, which raises exposure concern - the flaw is reachable pre-authentication against the Navigator web interface. However, impact is bounded: scope is unchanged (S:U) and the confidentiality/integrity impacts are both Low (C:L/I:L) with no availability impact (A:N), yielding a Medium 6.5 score rather than Critical. The practical effect is limited to altering server-side session security state rather than full authentication bypass with code execution or data exfiltration. No EPSS score, CISA KEV listing, or public POC is present in the provided data, so there is no evidence of active or imminent widespread exploitation. The signals are internally consistent - there is no CVSS-versus-description conflict - but exploitation probability data (EPSS) is entirely absent, so real-world weaponization likelihood cannot be quantified from the input. Treat this as a legitimate patch-in-cycle item for IBM i operators exposing Navigator, not an emergency, absent new exploitation intelligence.

Exploit ScenarioDerived

An unauthenticated attacker with network access to an IBM i Navigator endpoint sends a specially crafted HTTP request to any Navigator URL before logging in, manipulating the server-side session security state to weaken or bypass access-control restrictions. Because no credentials, user interaction, or special timing are required (AV:N/AC:L/PR:N/UI:N), the request can be issued directly against an exposed management interface. No public exploit code is identified in the provided data.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 20, 2026

Pre-authentication access control bypass in IBM i Navigator (7.3, 7.4, 7.5, and 7.6) lets a remote attacker alter server-side session security state by sending a crafted HTTP request to any Navigator URL before authenticating. The weakness is an improper authentication/access-control flaw (CWE-287) rated CVSS 6.5, with low confidentiality and integrity impact and no direct code execution or full account takeover; the practical risk is concentrated on Navigator interfaces that are reachable from untrusted networks. No public exploit code or confirmed active exploitation was identified at time of analysis.

RemediationAI

No vendor-released patch version is identified in the available data, so confirm fixed PTF or release levels directly from IBM's advisory at https://www.ibm.com/support/pages/node/7292223 before assuming any build is remediated; absence of a listed fix here is not confirmation that none exists. Until a fix is applied, restrict network access to the Navigator for i HTTP/HTTPS service to trusted administrative networks or VPN, and front it with an authenticating reverse proxy or gateway so unauthenticated requests cannot reach the application-accepting that this limits legitimate remote administration and that some Navigator features may break behind a proxy. Where Navigator is not required, disable the service entirely to remove the exposure, weighing the loss of browser-based administration against the reduced attack surface. Monitor web-server and Navigator logs for pre-authentication requests that mutate session state or arrive from unexpected sources, and treat such activity as attempted exploitation.

Affected VersionsENISA

i 7.4
i 7.5
i 7.6
i 7.3

Affected Packages

euvd i no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is CWE-287 (Improper Authentication): the Navigator for i web console fails to properly enforce access control on requests made before a session is authenticated, so a crafted HTTP request to any URL within the application can modify server-side session security state. Navigator for i is the browser-based administrative interface bundled with IBM i, and its session handling underpins authenticated administrative workflows; a pre-auth write primitive against session state can undermine later authorization decisions. The CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N) confirms the attacker needs only network reachability to the Navigator HTTP service, with no credentials and no user interaction, but the impact stays scoped to low confidentiality and integrity effects rather than system compromise. No CPE data was supplied; the affected platform releases are IBM i 7.3, 7.4, 7.5, and 7.6.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (us) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
vuln.today AI 6.5 MEDIUM

Pre-auth crafted HTTP request over the network gives AV:N/AC:L/PR:N/UI:N; altering session security state yields limited C:L/I:L with no availability impact and unchanged scope.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (us).

CVSS VectorVendor: us

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionCVE.org

IBM i 7.3, 7.4, 7.5, and 7.6 could allow an unathenticated remote attacker to bypass security restrictions due to improper access control. By sending a specially crafted HTTP request to any URL within the Navigator application prior to authentication, a bad actor could exploit this vulnerability to alter server-side session security state.

Threat Intelligence Overview

EPSS Score
0.4%
Top 68% exploitable
Prevalence
Medium
IBM i is a common enterprise midrange platform, but industry-concentrated not everywhere
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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